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nvme-rdma: don't complete requests before a send work request has completed

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In order to guarantee that the HCA will never get an access violation
(either from invalidated rkey or from iommu) when retrying a send
operation we must complete a request only when both send completion and
the nvme cqe has arrived. We need to set the send/recv completions flags
atomically because we might have more than a single context accessing the
request concurrently (one is cq irq-poll context and the other is
user-polling used in IOCB_HIPRI).

Only then we are safe to invalidate the rkey (if needed), unmap the host
buffers, and complete the IO.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Sagi Grimberg 2017-11-23 17:35:22 +02:00 committed by Christoph Hellwig
parent b4b591c87f
commit 4af7f7ff92
1 changed files with 24 additions and 4 deletions
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28
drivers/nvme/host/rdma.c
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@ -59,6 +59,9 @@ struct nvme_rdma_request {
struct nvme_request req;
struct ib_mr *mr;
struct nvme_rdma_qe sqe;
union nvme_result result;
__le16 status;
refcount_t ref;
struct ib_sge sge[1 + NVME_RDMA_MAX_INLINE_SEGMENTS];
u32 num_sge;
int nents;
@ -1162,6 +1165,7 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
req->num_sge = 1;
req->inline_data = false;
req->mr->need_inval = false;
refcount_set(&req->ref, 2); /* send and recv completions */
c->common.flags |= NVME_CMD_SGL_METABUF;
@ -1198,8 +1202,19 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
static void nvme_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
{
if (unlikely(wc->status != IB_WC_SUCCESS))
struct nvme_rdma_qe *qe =
container_of(wc->wr_cqe, struct nvme_rdma_qe, cqe);
struct nvme_rdma_request *req =
container_of(qe, struct nvme_rdma_request, sqe);
struct request *rq = blk_mq_rq_from_pdu(req);
if (unlikely(wc->status != IB_WC_SUCCESS)) {
nvme_rdma_wr_error(cq, wc, "SEND");
return;
}
if (refcount_dec_and_test(&req->ref))
nvme_end_request(rq, req->status, req->result);
}
static int nvme_rdma_post_send(struct nvme_rdma_queue *queue,
@ -1318,14 +1333,19 @@ static int nvme_rdma_process_nvme_rsp(struct nvme_rdma_queue *queue,
}
req = blk_mq_rq_to_pdu(rq);
if (rq->tag == tag)
ret = 1;
req->status = cqe->status;
req->result = cqe->result;
if ((wc->wc_flags & IB_WC_WITH_INVALIDATE) &&
wc->ex.invalidate_rkey == req->mr->rkey)
req->mr->need_inval = false;
nvme_end_request(rq, cqe->status, cqe->result);
if (refcount_dec_and_test(&req->ref)) {
if (rq->tag == tag)
ret = 1;
nvme_end_request(rq, req->status, req->result);
}
return ret;
}